modules/outputs/ubivolume: introduce ubinization

It creates an UBI image based on an UBI volume configuration.

For now, it creates only an empty rootfs.

modules/all-modules.nix

@@ -31,6 +31,8 @@
    ./ssh
    ./outputs/tftpboot.nix
    ./outputs/ubifs.nix
+   ./ubifs.nix
+   ./ubinize.nix
    ./users.nix
    ./vlan
    ./watchdog

modules/outputs/ubivolume.nix

@@ -0,0 +1,91 @@
+{
+  config
+, pkgs
+, lib
+, ...
+}:
+let
+  inherit (pkgs) liminix;
+  inherit (lib) mkIf mkOption types concatStringsSep optionalString;
+in
+  {
+    imports = [
+      ./initramfs.nix
+      ./ubifs.nix
+    ];
+
+    options.hardware.ubi = {
+      minIOSize = mkOption { type = types.str; };
+      eraseBlockSize = mkOption { type = types.str; }; # LEB
+      maxLEBcount = mkOption { type = types.str; }; # LEB
+    };
+
+    config = mkIf (config.rootfsType == "ubifs") {
+      kernel.config = {
+        MTD_UBI="y";
+
+        UBIFS_FS = "y";
+        UBIFS_FS_SECURITY = "n";
+      };
+      boot.initramfs.enable = true;
+
+      system.outputs.rootfs =
+      let
+        inherit (pkgs.pkgsBuildBuild) runCommand;
+        ubiVolume = ({ name, volumeId, image, flags ? [] }:
+        ''
+          [${name}]
+          mode=ubi
+          vol_id=${toString volumeId}
+          vol_type=dynamic
+          vol_name=${name}
+          vol_alignment=1
+          ${optionalString (image != null) ''
+            image=${image}
+          ''}
+          ${optionalString (image == null) ''
+            vol_size=1MiB
+          ''}
+          ${optionalString (flags != []) ''
+            vol_flags=${concatStringsSep "," flags}
+          ''}
+        '');
+
+        ubiImage = (volumes:
+        let
+          ubinizeConfig = pkgs.writeText "ubinize.conf" (concatStringsSep "\n" volumes);
+          inherit (pkgs.pkgsBuildBuild) mtdutils;
+        in
+        runCommand "ubinize" {
+          depsBuildBuild = [ mtdutils ];
+          # block size := 128kb
+          # page size := 2048
+          # ubninize opts := -E 5
+        } ''
+          ubinize -Q "$SOURCE_DATE_EPOCH" -o $out \
+            -p ${config.hardware.ubi.physicalEraseBlockSize} -m ${config.hardware.ubi.minIOSize} \
+            -e ${config.hardware.ubi.logicalEraseBlockSize} \
+            ${ubinizeConfig}
+        '');
+
+        ubiDisk = ({ initramfs }:
+        let
+          initramfsUbi = ubiVolume {
+            name = "rootfs";
+            volumeId = 0;
+            image = initramfs;
+            flags = [ "autoresize" ];
+          };
+        in
+          ubiImage [
+            initramfsUbi
+          ]);
+
+        disk = ubiDisk {
+          initramfs = config.system.outputs.rootubifs; # liminix.builders.squashfs config.filesystem.contents; #           # assert this is a proper FIT.
+        };
+
+      in
+        disk;
+  };
+}